Crap, gained 5 pounds

Well, I've gained 5 pounds in the last week. Doesn't make me very happy. I was doing well, but lately have been extremely tired, exhausted actually. Don't know if it is allergies or what. I really want to go and exercise, I mean my mind wants to, but my body is just to frigin tired. I see people out walking and jogging, but I am just to tired. I know someone will tell me to go to the doctor, but everytime I do, they do the same tests and tell me I am fine. It is so frustrating. I guess all I can do is ride it out and hope to hell this exhausted feeling goes away soon.

Any hints on what to do? I started to take claritin today, maybe that will help?